Some writing instruments, e.g., pens and markers, include erasable inks which allow markings formed with the ink to be erased. It is desirable that such inks be easily erased using a conventional eraser, that erasure be substantially complete, and that it be possible to erase the marking both immediately after the marking is made and after a period of time has elapsed. It is also desirable that erasable inks provide good writing performance when compared with non-erasable inks.